There are two major takeaways from the Congressional Budget Office’s analysis of the president’s proposed 2012 budget. The first is that the CBO doesn’t believe it will save as much money as the White House says it will. The second is that doing nothing — yes, nothing — would do more to cut the deficit than anything that the Obama White House proposed or than the GOP is likely to propose.

On the question of the president’s budget itself, CBO projects that public debt would increase to 87 percent of GDP over the next 10 years. The Obama administration’s projections put that at 77 percent. The difference appears to be that the CBO is more pessimistic about the economic outlook over the next decade — a pessimism that matters enormously for deficit projections.

Who’s right? Well, predictions are hard. As Jon Chait details, there was a similar dispute in the 1990s where the Clinton White House was using more optimistic projections than the CBO — and the Clinton White House not only proved closer than the CBO, but even their relatively optimistic projection proved overly pessimistic. This time, of course, things might not turn out as rosy. But that’s a guessing game. What’s not a guessing game is that the Obama budget increases the deficit versus a policy of doing nothing, as a policy of doing nothing means that all the Bush tax cuts expire in full while the Obama budget keeps all of them, aside from the tax cuts for the rich.

The difference in revenues is pretty clear on that graph. But if you’re wondering why Obama’s budget leads to a slight bump in spending, too, it turns out that that’s also a revenues issue: “Outlays would be greater under the President’s budget than in CBO’s baseline in each of the next 10 years, primarily because the proposed reduction in revenues would boost deficits and thus the costs of paying interest on the additional debt that would accumulate.”

My prediction, incidentally, is that this will hold true — perhaps even more true — for the Republican budget, which also won’t repeal the Bush tax cuts. Which will mean that over the next 10 years, both the Republican and Democratic budgets will be worse for the deficit than inaction because neither the Republican nor Democratic budgets will call for the full expiration of the Bush tax cuts, which is what’s written into law law — and thus the CBO’s baseline — right now.